Hi Brian,
If you can lay down 4 vias in a straight line on your PCB, then you can
use something like this (from pine64.com):
https://pine64.com/product/pinetime-pogopin-jig/
I use these to program my pinetime smart watches where space is at a
premium. Here's a wiki page with lots of pictures to show how it's used:
https://wiki.pine64.org/wiki/PineTime_Devkit_Wiring
Maybe it's useful, maybe it's not, but it's worth a look. :-)
Regards, Bert
On 1/13/23 13:26, Brian K. White wrote:
As the Molex sockets are no longer made, and as I like making custom rom
boards that fit in the socket and I always want the module to be
user-re-programmable after the fact, I am always trying to figure out
some practical solution to connecting the assembled module to a
programmer without needing an actual original socket.
I happen to have a whole bunch of real sockets, and you can even still
find some old stock on line.
https://www.dhgate.com/product/for-molex-dip28p-ic-chip-socket-silver-plated/372020519.html
But that's beside the point. They'll eventually be gone and they are
hardly convenient even now while they do still exist. So I'm still
always keeping an eye out and trying to figure something out that uses
more generic always available parts, and not requiring some hand crafted
custom fabrication, something that anyone can do. But it's a tough problem.
Up to now, I've mostly just relied on limiting to having the board use
an SOIC chip, which are small enough to fit in the available space, yet
large enough to make a test clip practical. This is like the old ROMBO &
MOMBO shown on club100. But that still requires an soic-28 test clip
which are not exactly common, and not exactly convenient given the need
to hook up the wires.
http://tandy.wiki/images/f/f8/Teeprom_10.jpg
To get away from the soic test clip, and the limitation of only being
able to use an soic part, I am currently waiting for shipment to test
another idea:
https://github.com/bkw777/Teeprom/blob/master/4ROM.md
The connection seems to work well, the testing part is just that my last
version I had a totally wrong pinout on the programming adapter. So I
re-did the programming adapter and I can't call it good until I actually
build one and use it.
It's more convenient to use than the test clip, and allows using any
kind of parts on the board like that TSOP chip there, not just things
that they make practical test clips for, and it requires no special
parts. The pins are completely standard and you will be able to buy the
pins probably forever while the test clip I think is already only new
old stock by now. But even this is really kind of a pain. That is a lot
of real estate used up for those holes, and it sure made routing the
traces a challenge, and that's just for a simple thing like that with a
single chip and almost no actual circuitry. The whole board is filled
with holes and traces just to do nothing but simply provide two sets of
connection pints for that one chip.
What would be ideal is just have a socket that could use the edge
contacts instead of needing a whole 2nd set of contacts, but, back to
the top, not a currently manufactured part...
And finally the point of this email, just now I saw something interesting:
https://lectronz.com/products/flexypin-pack-of-100
Obviously not useful as a replacement socket inside the machine to
repair a mangled one, but looks ideal to make a programming adapter to
plug in to eprom programmers.
I'm *guessing* that the pcb makes it reasonably practical to solder the
pins. I imagine the way it works is when you stick the pin in the slot &
hole, it holds itself in place from the tension, so you can (I assume)
stick all the pins in and then solder them relatively simply.
I have a half-baked idea for a 3d-printed clone of the original socket
with either bent gold plated brass wire like what I use to make dip
legs, or maybe with a custom ffc that goes inside. In either case the
plastic part would provide the springy pressure to push the contacts
onto the module.
Or some other idea using a bunch of pogo pins laying on their sides, but
it just doesn't seem like a great answer.
But this looks pretty interesting because although it looks like it
might be a single oddball part made by a single manufacturer instead of
something standard that anyone will always be able to get, it at least
looks nice and simple. Just a pcb and the pins. And $6 for 100 pins is
way better than like MillMax $1 per pin for some of their specialty pins.
